The present invention relates to a racket structure and more particularly to an improved structure of a composite fiber racquet.
According to the manufacturing of composite fiber rackets as adopted in the prior art, a polyethylene tube, of oblate form, is generally covered with a layer of fiber, then put into a molding die with an opening through which high-pressure heated air from a pump is blown in to complete the molding process. Alternately, the polyethylene tube can be filled with expandable polyurethane to form the tube within the mold.
A major deficiency of these methods is that when the polyethylene tube is placed in the mold the inner side thereof tends to wrinkle upon bending. Making it impossible to keep the thickness of the fiber layer even. Consequently, at the positions of the through-holes, after the head frame is strung, cracks tend to occur due to the stress concentrations from the taut strings. Thus the wrinkling of the inner side not only degrades the appearance of the racquet but also reduces the service life of the head frame.